This invention relates to a hydraulic fuse, and, more particularly, to a hydraulic pressure fuse which is normally closed and which opens when downstream fluid pressure reaches a predetermined operating pressure and which closes when downstream pressure falls below the operating pressure.
A hydraulic fuse is interposed in a hydraulic fluid line for closing fluid flow through the line when downstream pressure is lost, for example, when the line ruptures. Hydraulic fuses are commonly called velocity fuses, quantity fuses, excess flow protectors, automatic stop valves, safety valves, etc. Such fuses are conventionally normally open valves and are actuated when fluid flow or volume exceeds a preset rate.
The invention provides a hydraulic pressure fuse which is a normally closed valve and which is operated by differential pressure between the upstream and downstream sides of the valve. The valve is opened when the downstream pressure reaches a predetermined operating pressure. If the downstream pressure falls below the operating pressure, the valve closes regardless of the upstream pressure, flow rate, or volume. The valve resets automatically and includes a manual override and position-indicating pin.